3. 畫Sin 及 Cos 函數圖形

using System.DirectoryServices.ActiveDirectory;

namespace Q3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            Close();
        }

        bool draw = false;
        private void button1_Click(object sender, EventArgs e)
        {
            draw = true;
            panel1.Refresh();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            draw = false;
            panel1.Refresh();
        }

        private void panel1_Paint(object sender, PaintEventArgs e)
        {
            if (!draw) return;

            e.Graphics.DrawLine(new Pen(Brushes.Red, 2), 0, 360 / 2, 720, 360 / 2);
            if (radioButton1.Checked)
            {
                for (int i = 0; i < 360; i++)
                {
                    e.Graphics.FillEllipse(Brushes.Black, i * 2,
                        175 - (int)(170 * Math.Sin(double.DegreesToRadians(i))), 5, 5);
                }
            }
            if (radioButton2.Checked)
            {
                for (int i = 0; i < 360; i++)
                {
                    e.Graphics.FillEllipse(Brushes.Black, i * 2,
                        175 - (int)(170 * Math.Cos(double.DegreesToRadians(i))), 5, 5);
                }
            }
        }
    }
}